Self-directedness
Insights from Geneticist, author and filmmaker, Dean Hamer, Ph.D.
There are people who are able to adapt their behavior to accommodate whatever their own goals and values are. If they want X, then they will do Y to get it. They rely on themselves. They feel like they have a purpose in life, and they do whatever is necessary to achieve that end. It's really all a matter of what personality psychologists sometimes call self-directedness, also commonly referred to as self-reliance or even self-esteem.
People who are not self-directed tend to do things in reaction to outside forces, what other people want, or circumstances that envelop them at the moment. They continue to do the same behaviors even when it's not achieving what they want or even when it's not consistent with their own value system. They're low on self-reliance and frequently don't attain what they want.
Self-directedness is about 50 percent genetic.
There’s a lot that people can do to change behavior and thereby change their brain chemistry. However, one’s inborn DNA genetic makeup does tend to tilt the scales and make it easier or more difficult for some people to change than it is for others.